Chickenpox

Chickenpox is a highly contagious viral illness that causes a red, itchy rash that forms blisters.

Chickenpox is a highly contagious virus that causes a red, itchy rash.

For most people chickenpox will be mild and resolves by itself.

Treatments include rest, calamine lotion and paracetamol.

In Australia a vaccine is available to protect against the infection.

What it is

Chickenpox is a highly contagious viral illness that causes a red, itchy rash that forms blisters. It's caused by the varicella zoster virus, which is part of the herpes group of viruses. Anyone can get chickenpox but it's most common among children under 12 and is usually a relatively mild illness. In adults or for anyone with impaired immunity, the infection can be more severe.

The virus that causes chickenpox is the same virus that causes shingles in adults. Shingles occurs when the chickenpox virus stays in the nerve cells after a chickenpox infection becomes active again. It only occurs in people who've already had chickenpox.

Chickenpox is spread through coughing and sneezing during the early stage of infection and through contact with the fluid from the broken blisters of the rash in later stages of the illness. The infection is especially contagious to those who haven't been immunised or have never had chickenpox. Once you've had chickenpox it's unlikely to reoccur.

The onset of chickenpox usually starts about 10 to 21 days after you catch the virus. Symptoms include:

Fever

Headache

Sore throat

Backache

Generally feeling unwell

Skin rash - clusters of spots that are usually very itchy. These spots start as small lumps that turn into blisters then scabs. They take about 16 days to heal.

Complications of chickenpox include scarring and cellulitis (a type of bacterial infection of the skin). Sometimes the infection can cause serious complications such as pneumonia and encephalitis (inflammation of the brain). Very rarely chickenpox can be fatal.

Doctors will diagnose chickenpox through a physical examination. Blood tests and tests of blister fluid may also be carried out to confirm the diagnosis.

Who it affects

Chickenpox was common before national immunisation high-risk groups include:

Newborns

Pregnant women who haven't had chickenpox or been immunised

People with weakened immunity systems

How to prevent it

The best protection against chickenpox is immunisation. In Australia, children are immunised when they are 18 months old and in Year 7 of secondary school. Immunisation is also recommended for people in high-risk jobs such as healthcare, childcare and teaching.

The vaccine should not be given during pregnancy. Side effects from immunisation are uncommon in healthy people.

How to treat it

Most people with chickenpox will get better without any specific treatment. To help relieve symptoms rest, drinking plenty of fluids and paracetamol to treat the fever will be recommended.